This invention relates to a flanged honeycomb core structure and method of fabricating the same. A metallic honeycomb core structure which is laser-welded is shown in U.S. Pat. No. 5,437,936, the disclosures and teachings of which are incorporated herein by reference.
A core structure of the type disclosed in U.S. Pat. No. 5,437,936 does not incorporate flanges but, rather, includes at the opposite extremities of the cells a very thin edge which is customarily secured, in the case of metallic foil honeycomb core, to the inner surface of facing sheets to define a structural panel. It is not necessary to braze the metallic honeycomb core structure to the facing sheets which is a complicated and expensive process and which materially increases the weight of the structural panel which results from such brazing. Most metallic honeycomb core is glued to the face sheets. The flanged core disclosed herein can be brazed, glued, resistance welded, or diffusion bonded to face sheets.
In paper or paper-like honeycomb core structures, the honeycomb core is glued to the inner surfaces of facing sheets which are customarily provided in the form of paper or paper substitutes or which may, on occasion, be fabricated from metallic foil.
Where the utilization of glue occurs, it adds materially to the weight of the resultant panel because the glue must be spread across the contacting surfaces of the honeycomb core and face sheets, thus adding to the amount and weight of glue in the resulting panel.
Although the teachings of the ""936 patent are directed to the use of the laser weldment between adjacent sheets of metallic foil, the teachings of the present invention are relevant to both paper and paper substitutes and various types of flexible materials, including metallic foils of the character disclosed in the ""936 patent since the formation of the flange tabs on paper or metallic structures can be accomplished by identical method steps.
It is, therefore, an object of my invention to provide an assemblage of flexible sheets or strips of material which are arranged in superimposed, stacked relationship with the assemblage having opposite longitudinal sides and upper and lower surfaces and the superimposed sheets having surfaces in engagement with and secured to each other at alternate locations to provide a honeycomb core configuration when the assemblage is expanded to assume said honeycomb core configuration, said sides having flange tabs thereupon.
A further object of my invention is the provision of such an assemblage in which securement means depending on the nature of the stacked material is provided. In the case of paper or paper-like materials, various types of glues, including resinous glues can be applied to the sheets of paper or paper-like material at the intervals determining the shape of the cells of the resultant honeycomb core. On the other hand, if the teachings of the ""936 patent are followed, the foil sheets or strips can be secured to one another by the laser weldments disclosed in said patent.
An additional object of my invention is the provision on the opposite sides of said assemblage, whether fabricated from paper or paper-like materials or metallic foils, of flange tabs capable of being deformed into flanges on the honeycomb core structure after expansion of the assemblage to define said honeycomb core structure.
An additional object of my invention is the provision of an assemblage of the aforementioned type in which the flange tabs are defined by cutting or grooving the opposite sides to provide the desired shape and size of the flange tabs.
Another object of my invention is the provision of a method of fabricating the flange tabs which includes the grooving of the opposite sides of the assemblage.
A further object of my invention is the provision of a method of providing flanges upon the opposite sides of the aforesaid honeycomb core by deforming the flange tabs on said sides.